The Prohibition era in America, which lasted for well over a decade and—inconceivable as it might be today—effectively banned the sale and production of booze in the United States, ended with the ratification of the 21st Amendment on Dec. 5, 1933.

Six months ago, TIME began to plan and gather materials for what would become “One Dream” — a multimedia commemoration of the 1963 March on Washington and the 50th anniversary of Martin Luther King Jr.’s “I Have a Dream” speech. From a purely photographic perspective, the project involved research on a titanic scale, with photo editors poring over literally thousands of images by photojournalism greats, many of whom — Paul Schutzer, Charles Moore, Grey Villet, Stanley Tretick, Flip Schulke and others — are no longer with us. Living masters like Bob Adelman, Dan Budnik and Steve Schapiro, meanwhile, were welcome collaborators, helping to shape the direction of “One Dream” not only with their pictures, but their stories.

“Adelman’s insights and memories were invaluable,” notes Phil Bicker, senior photo editor at TIME and the creative lead on the project. “For instance, he was the one who insisted, in the very first conversation I had with him, that if we were doing something on the march, we simply couldn’t do it without discussing the violence in Birmingham earlier that year, in the spring of 1963.”

“Then there was Dan Budnik, who was always available to talk and whose style and approach — he took the chance of shooting MLK from behind during his speech, for example — brought a distinctive visual depth to the project. Steve Schapiro personally sent us numerous images from his own archive, while talking with photographers like John Goodwin and Ivan Massar about the march and the movement as a whole was simply fascinating.”

Above and beyond the stellar still photography — much of it never published before — there are the site’s remarkable videos, including interviews shot by Marco Grob with major figures from the civil rights movement, as well as portions of Oscar-winning cinematographer Haskell Wexler’s early documentary film, The Bus. Finally, there are the informal, amateur photographs that TIME culled from submissions by people who were there, and who wished to share their stories and their personal photos from the march.

All these elements, and many, many others, combine in “One Dream” to pay tribute to the spirit of the March on Washington and the enduring legacy of Martin Luther King Jr. and the civil rights movement.